Compounded lubricant



Patented June 15, 1943 COMPOUNDED LUBRICANT James 0. Clayton and Bruce B. Farrington, Berkeley, Calif., asslgnors to Standard Oil Company of California, San Francisco, Calif., a corporation of Delaware No Drawing. ApplicationJune 10, 1940,

Serial No. 339,662

29 Claims.

This invention relates to a new and useful composition of matter comprising a compounded hydrocarbon oil. More particularly, it involves the provision of a lubricating oil containing metalsalts of organic acids and an addition agent which inhibits undesirable effects of such compounds, as set forth hereinafter.

Metal salts of organic acids are known as compounding ingredients for lubricating oils and have been added thereto for various purposes. For example, aluminum oleate is disclosed as a dispersing agent for graphite in the United States Patent to Burke No. 1,732,221, various soaps have been disclosed as pour point depressing agents, and the patent to Parker No. 2,001,108 is directed to metal naphthenates as stabilizing agents for lubricating oils. In its broader aspects this invention is applicableto compounded oils containing metal salts of organic acids of the above known types, as well as to oils containing novel types of salts hereinafter disclosed. The present invention, in its more specific aspects, is concerned with oils compounded with certain metal salts among which are polyvalent metal salts, such as salts of aluminum, zinc, tin magnesium, calcium and chromium.

One important property of lubricating oils is low corrosivity, especially with respect to modern bearing metals such as copper-lead or cadmiumsilver alloys. Some lubricating oils which have been entirely satisfactory from the standpoint of corrosivity to high grade Babbitt bearing metals show a corrosion rate which is greater than is desirable with bearing metals of a type represented by cadmium-silver and copper-lead bearings. Lubricating oils containing metal salt compounding ingredients have been found, in general, to show undesirable corrosive effects on such bearing materials. However, these metal salt compounding ingredients are highly desirable or even necessary for other purposes, such as for inhibiting piston ring sticking in internal combustion engines such as Diesel engines.

Accordingly, it is an object of the invention to solve the above difllculties by providing an improved compounded mineral oil containing metal salts of organic acids.

Another object of the invention is to inhibit corrosive effects of compounded lubricating oils containing metal salts of organic acids.

A further object of the invention is to increase the stability of lubricating oils with respect to oxidation or discoloration or gum formation.

A still further object is to improve the properties of lubricating oils containing metal salts of organic acids by incorporating therein an ester containing as a substituent an element of the phosphorus group in a trivalent state, said element being no more than two carbon atoms from a carbonyl group of said ester.

Additional objects and advantages of the invention will becom apparent from the disclosure which follows.

Examples of metal salts of organic acids which may be incorporated in lubricating oils according to the principles of this invention are metal salts of higher fatty or aliphatic acids, metal salts of naphthenic acids, metal salts of oil-soluble substituted phenols, and metal salts of carboxylic acids containing an aryl substituent.

Among the metal salts of higher fatty acids may be mentioned: aluminum laurate, aluminum oleate, aluminum stearate, aluminum ricinoleate; zinc laurate, zinc oleate, zinc stearate, zinc ricinoleate; tin laurate, tin oleate, tin stearate, tin ricinoleate; magnesium laurate, magnesium oleate, magnesium stearate, magnesium ricinole'ate; calcium laurate, calcium oleate, calcium stearate, calcium ricinoleate; chromium laurate, chromium oleate, chromium stearate,

and chromium ricinoleate,

Examples of metal naphthenates are: aluminum naphthenate, zinc naphthenate, magnesium naphthenate, cobalt naphthenate, cadmium naphthenate, tin naphthenate and manganese naphthenate. The naphthenic acid component of these salts may convenientlybe obtained from petroleum.

Metal phenates which may be mentioned comprise metal salts of a substituted phenol of the type formula:

in which u, v, w, a: and y are selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl and cyclic non-benzenoid hydrocarbon radicals. Specific illustrations of such phenates are the aluminum, zinc, ti-n, magnesium, calcium and chromium as well as other polyvalent metal salts of cetyl phenol. The phenolic radical of the salts preferably contains more than about ten carbon atoms and also should preferably have an alkyl substituent substituted in the benzene ring to which the hydroxyl group of the phenol is directly attached.

Examples of carboxylic acids containing an aryl substituent are: phenyl stearic acid, naphthyl stearlc acid, phenyl lauric acid, alpha benzal stearic acid, alpha benzal lauric acid, and analogous homologues of these acids formed by condensation of an aromatic aldehyde with a fatty acid according to the reaction:

where R1 is an alkyl and R2 an aryl radical. Aluminum, zinc, tin, magnesium, calcium and chromium as well as other polyvalent metal salts of each of the above acids may be utilized.

The invention also includes salts of polycarboxylic acids together with esters containing an element of the phosphorus group in a trivalent state, in hydrocarbon oils. Examples of such salts are the aluminum, zinc, tin, magnesium, calcium and chromium as well as other polyvalent metal salts of partially esterifled acids of the oxalic acid isosuccinic or methyl malonic acid and its alkyl homologues, as well as the corresponding salts of partially esterified alkyl tartronic acid, partially esterified malic acid and its homologues, partially esterifled oxyglutaric acid, partially esterifled hydroxy adipic acid, partially esterified tartaric acid, partially esterified citric acid and the like.

The second component of the composition of this invention comprises oil-soluble esters containing as a substituent an element of the phosphorus group in a trivalent state, said element being no more than two carbon atoms from a carbonyl group of said ester. These types of esters may be represented generically by the following structural formulae:

Alpha substituted ester m-on-c-z-m Beta substituted esters Ri-C--ZCHr-CH-R:

In these formulae R1 and R2 represent an alkyl, aryl, alkaryl, aralkyl or cyclic non-benzenoid group. R1 and R2 may contain substituents other than the trivalent element of the phosphorus group, which substituents may be of either the same or a different type. In the formulae Y and Z may be either oxygen or sulfur; X represents a trivalent element of the phosphorus group, and may be present in any one of the following radicals:

where R: and R4 may be an alkyl, aryl, alkaryl, aralkyl or cyclic non-benzenoid hydrocarbon radical series, including oxalic acid itself, malonic acid,

In the type formulae given herein, frequent reference ismade to alkyl, aryl, alltaryl, aralkyl or cyclic non-benzenoid radicals. Examples of alkyl radicals are: methyl, ethyl, propyl. butyl, amyl, hexyl, heptyl, octyl, nonyl, decyl, do'decyl (lauryl), tetradecyl and cetyl. Examples of aryl radicals are phenyl and naphthyl. Examples of alkaryl radicals are radicals in which a benzene ring is attached directly to the molecule being substituted, and the benzene ring contains an alkyl substituent. Examples of aralkyl radicals are radicals in which an alkyl group is attached directly to the molecule being substituted, and the alkyl group contains an aryl substituent, for instance, an ester 0! phenyl methyl alcohol. Ex-

amples of cyclic non-benzenoid radicals are cyclopentyl, cyclo hexyl and cyclo heptyl.

Examples of alpha substituted esters are esters of phosphino-acetic acid, esters of alpha phosphino-propionic acid, esters of alpha phosphinobutyric acid, esters of alpha phosphino-valeric acid, esters of alpha phosphino-caproic acid, esters of alpha phosphino-caprylic acid, esters of alpha phosphino-capric acid, esters of alpha phosphino-lauric acid, esters of alpha phosphinomyristic acid, esters of alpha phosphino-palmitic acid, esters of alpha phosphino-stearic acid, esters of alpha phosphino-arachidic acid; esters of arsino-acetic acid, esters of alpha arsino-propicnic acid, esters of alpha arsino-butyric acid, esters of alpha arsino-valeric acid, esters of alpha arsino-caproic acid, esters of alpha arsinocaprylic acid, esters of alpha arsino-capric acid. esters of alpha arsino-lauric acid, esters of alpha arsino-myristic acid, esters of alpha arsinopalmitic acid, esters of alpha arsino-stearic acid, esters of alpha arsino-arachidic acid; esters of stibino-acetic acid, esters of alpha stibino-propionic acid, esters of alpha stibino-butyric acid, esters of alpha stibino-valeric acid, esters of alpha stibino-caproic acid, esters of alpha stibinocaprylic acid, esters of alpha stibino-capric acid. esters of alpha stibino-lauric acid, esters of alpha stibino-myristic acid, esters of alpha stibinopalmitic acid, esters of alpha stibino-stearic acid, and esters of alpha stibino-arachidic acid.

.Examples of beta substituted esters comprise esters of beta pho'sphino-propionic acid, esters of beta phosphino-butyric acid, esters of beta phosphino-valeric acid, esters ofbeta phosphinocaproic acid, esters of beta phosphino-caprylic acid, esters of beta phosphino-capric acid, esters of beta phosphino-lauric acid, esters of beta phosphino-myristic acid, esters of beta phosphino-palmitic acid, esters of beta phosphinostearic acid, esters of beta phosphino-arachidic acid; esters of beta arsino-propionic acid, esters of beta arsino-butyric acid, esters of beta arsinovaleric acid, esters of beta arsino-caproic acid. esters of beta arsino-caprylic acid, esters of beta arsino-capric acid, esters of beta arsino-lauric acids, esters of beta arsino-myristic acid, esters of beta arsino-palmitic acid, esters of beta arsinostearlc acid, esters of beta arsino-arachidic acid; esters of beta stibino-propionic acid, esters of beta stibino-butyric acid, esters of beta stibinovaleric acid, esters of beta stibino-caproicacid, estersof beta stibino-caprylic acid, esters of beta stibino-capric acid, esters of beta stibino-lauric acid, esters of beta stibino-myristic acid, esters of beta stibino-palmitic acid, esters of beta stibino-stearic acid, and esters of beta stiblnoarachidic acid.

The esters of this invention may be prepared by any suitable method; for example, by esterie flcation of the alpha or beta substituted acids, by

esterification of the alpha or beta substituted alcohols, or by introducing the trivalent element of the phosphorus group into an ester in an alpha or beta position. By way of exemplification: Heat benzo-nitrile and P013 with aluminum chloride for several hours, treat this mixture with dilute hydrochloric acid, extract with ether and wash aluminum chloride from the ether solution, distill oif the ether and fractionally distill the prodnot, treat the resulting nitrile with alcoholic potassium hydroxide for several hours. This produces the potassium salt of a phosphino substituted benzoic acid. Suspend this in excess amyl alcohol and pass dry HCl through the suspension, and then fractionally distill.

It will be understood from the foregoing discussion that the invention embraces the moor-- poration of both a. metal salt of an organic acid and the substituted ester as addition agents for liquid lubricating oils. Each and every one of the foregoing metal salts of organic acids may be utilized in hydrocarbon oils with each and every one of the foregoing substituted esters to impart improved properties to the oil; e. g., lubrieating oils containing any one or more of the metal salts of fatty acids with any one or more of the alpha or beta phosphino, arsino or stibino substituted esters will be found useful. Likewise, oils containing any one or more of the metal naphthenates in combination with any one or more of the alpha or beta phosphino, arsino or stibino substituted esters possess advantageous properties. The same is true of combinations of any one or more of the metal salts of phenols or the metal salts of the aryl substituted or polycarboxylic acids with any one or more of said substituted esters.

The combinations disclosed herein cooperate to give new results in hydrocarbon lubricating oils. In general, the alpha or'beta phosphino, arsino or stibino substituted esters reduce the corrosive effects of hydrocarbon. oils on modern bearing metals, such as copper-lead or cadmium-silver alloys. These esters will reduce corrosiveness of oils containing metal salts of organic acids as much as 50% or more. Various of the metal salts of organic acids and the substituted esters apparently cooperate to enhance the stability'of the oil against discoloration, gum formation, piston ring sticking and the like.

The proportions of addition agents utilized will depend upon the particular compound incorporated in the oil, upon the base oil being compounded, as well as upon the conditions which the oil is to encounter during. use and the properties desired. In general, from 0.1% to of the metal salts of organic acids are utilized, and more usually 0.5% to 2% thereof are found desirable. Measurable improvements in the properties of the compounded oil are obtained with as little as 0.1% of the substituted esters, but as much as 1% is preferred. More than is regarded as unnecessary.

The chemical mechanism by which the results of this invention are obtained has not been established. Metal salts of organic acids appear gensaltsof organic acids; 1. e., the alpha or beta phosphino, arsino or stibino substituted esters may, according to the broader principles of the invention, be utilized to inhibit the corrosive action of hydrocarbon lubricating oils on copperlead and cadmium-silver bearing metals whether or not the oils contain metal salts. However, the invention appears to find its greatest utility in oils containing metal salts of organic acids in that these salts cooperate with the esters to yield properties which are not obtainable with either type of component alone.

It is apparent that the particular ester and the particular metal salt must be selected with various factors in mind, such as the service to be encountered and the type of bearings or other machine elements to be lubricated, if the maximum benefits of the invention are to be obtained. In general, salts containing at least ten carbon atoms are preferred. Where reduced corrosion is desired esters containing less than ten carbon atoms are preferred. Esters containing more than ten carbon atoms are useful for imparting other properties to the oil, e. g., reducing wear or reducing friction. While specific examples and methods of preparation of the compositions of the invention have been described, this has been done by way of illustration only and with the intention that no limitation should be imposed upon the invention thereby. Numerous modifications and variations of the illustrative examples may be effected in the practice of the invention'which is of the scope of the claims appended hereto.

We claim:

1. A composition of matter comprising a hydrocarbon oil containing a metal salt of an organic acid in an amount sufficient substantially to increase the corrosivity of said oil, and a corrosion inhibitor for reducing said increased corrosivity comprising an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group of said ester.

2. A composition of matter comprising a hydrocarbon oil containing a metal salt of an organic acid in an amount suflicient substantially to increase the corrosivity of said oil, and a corrosion inhibitor for reducing said increased corrosivity comprising an ester having a phosphino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

3. A composition of matter comprising a hydrocarbon oil containing a metal salt of an organic acid in an amount suflicient substantially to increase the corrosivity of said oil, and a corrosion inhibitor for reducing said increased corrosivity comprising an ester having an arsino substituent no more than two carbon atoms re moved from a carbonyl group of said ester.

4. A composition of matter comprising a hydrocarbon oil containing a metal salt of an organic acid in an amount suiiicient substantially to increase the corrosivity of said oil, and a corrosion inhibitor for reducing said increased corrosivity comprising an ester having a stibino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

5. A compounded hydrocarbon oil containing a small amount of a metal salt of an organic acid, and from approximately 0.1% to 10% of an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group of said ester.

7. A compounded hydrocarbon oil containing a small amount of a metal salt of an organic acid, and from approximately 0.1% to of an ester having an arsino substituent no more than two carbon atoms removed from a carbonyl group oi said ester.

8. A compounded hydrocarbon oil containing a small amount of a metal salt of an organic acid, and from approximately 0.1% to 10% of an ester having-a stibino substituent no more than two carbon atoms removed from a carbonyl group oi said ester.

9. In a method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces. one of which is a bearing metal of the type represented by cadmium-silver and copperlead alloys, a film of a lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode said bearing metal, the step of inhibiting the corrosive action of the oil on said bearing by incorporating therein from approximately 0.1% to 10% of an ester having an element of the phosphorus group in a trivalent state substituted on an alkyl carboh atom and no more than two carbon atoms removed from a carbonyl group of said ester.

10. In a method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which is a bearing metal of the type represented by cadmium-silver and copper-lead alloys. a film of a lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode said bearing metal, the step of inhibiting the corrosive action of the oil on said bearing by incorporating therein from approximately 0.1% to 10% of an ester having a phosphino substituent no more than two carbon atoms removed from a, carbonyl group of said ester.

11. In a method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which is a bearing metal of the type represented by cadmium-silver and copper-lead alloys, a film of a lubricating oil which initially produce an effective lubricating action but which would normally tend to corrode said bearing metal, the step of inhibiting the corrosive action of the oil on said bearing by incorporating therein from approximately 0.1%

to 10% of an ester having an arsino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

12. In a method of lubricating bearing surfaces which.cornprises maintaining between the bearing surfaces, one of which is a bearing metal of the type represented by cadmium-silver and copper-lead alloys, a film of a lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode said bearing metal, the step of inhibiting the corrosive action of the oil on said bearing by incorporating therein from approximately 0.1% to 10% of an ester having a stibino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

13. In a method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which is a bearing metal of the type represented by cadmium-silver and copper-lead alloys, a film of a compounded lubricating oil containing a metal salt of an organic acid in an amount which would normally increase the corrosivity of said oil to said bearing metal, the step of inhibiting the increased corrosive action of the salt-containing oil on said bearing by incorporating therein from approximateLv 0.1% to 10% of an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group of said ester.

14. In a method of lubricating bearing surfaces which comprises maintaining between the bearing surfaces, one of which is a bearng metal of the type represented by cadmium-silver and copper-lead alloys, 2. film of a compounded lubricating oil containing a metal salt of an organic acid in an amount which would normally increase the corrosivity of said oil to said bearing metal, the step of inhibiting the increased corrosive action of the salt-containing oil on said hearing by incorporating therein from approximately 0.1% to 10% of an ester having a phosphino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

15. A compounded hydrocarbon oil containing a corrosion inhibitor comprising an aliphatic ester having an element of the phosphorus group in a trivalent state substituted on an alkyl carbon atom and no more than two carbon atoms removed from a carbonyl group of the ester.

16. A compounded hydrocarbon oil containing a corrosion inhibitor containing a characterizing chemical group of the type formula:

R1CHCZR:

in which R1 and R2 are radicals of hydrocarbon structure; Y and Z are selected from the group consisting of oxygen and sulfur; and X represents an element of the phosphorus group in a trivalent state.

17. A compounded hydrocarbon oil containing a corrosion inhibitor containing a characterizing chemical group of a type formula selected from the group consisting of:

and

in which R1 and R2 are radicals of hydrocarbon structure; Y and Z are selected from the group consisting of oxygen and sulfur; and X represents an element of the phosphorus group in a trivalent state.

18. A compounded lubricant comprising a hydrocarbon oil containing a metal salt of an organic acid in an amount sufficient substantially to increase the corrosivity of said oil, and a corrosion inhibitor for reducing said increased corrosivity comprising an ester containing a characterizing chemical group of the type formula:

Rr-(FH-C-Z-Jh in which R1 and R2 are radicals of hydrocarbon structure; Y and Z are.selected' from the group consisting of oxygen and sulfur; and X represents an element of the phosphorus group in a trivalent state.

19. A compounded lubricant comprising a hydrocarbon oil containing a metal salt of an organic acid in an amount sufiicient substantially to increase the corrosivity of said oil, and a corrosion inhibitor for reducing said increased corrosivity comprising an ester containing a characterizing chemical group of a type formula selected from the group consisting of:

in which R1 and R2 are radicals of hydrocarbon structure; Y and Z are selected from the group consisting of oxygen and sulfur; and X represents an element of the phosphorus group in a trivalent state.

20. A lubricant comprising a major proportion of hydrocarbon oil with the properties of said composition affecting its use as a lubricant improved by incorporating therein at least 0.1% by weight based on the oil of a metal salt of an organic acid and from approximately 0.1% to by weight based on the oil of an ester hav- 1' ng a substituent no more than two carbon atoms removed from a carbonyl group of said ester,

said substituent comprising an element of the phosphorus group in a trivalent state.

21. A lubricant comprising a major proportion of hydrocarbon oil with the properties of said composition affecting its use as a lubricant improved by incorporating therein at least 0.1% by weight based on the oil of a metal salt of an organic acid and from approximately 0.1% to 10% by weight based on the oil of an ester having a phosphino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

22. A lubricant comprising a major proportion of hydrocarbon oil with the properties of said composition aflecting its use as a lubricant improved by incorporating therein at least 0.1% by weight based on the oil of a metal salt of an organic acid and from approximately 0.1% to 10% by weight based on the oil of an ester having an arsino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

23. A lubricant comprising a major proportion of hydrocarbon oil with the properties of said composition affecting its use as a lubricant improved by incorporating therein at least 0.1% by weight based on the oil of a metal salt of an organic acid and from approximately 0.1% to 10% by weight based on the oil of an ester having a stibino substituent no more than two carbon atoms removed from a carbonyl group of said ester.

24. A compounded hydrocarbon oil containing a metal salt of a carboxylic acid in an amount suflicient substantially to increase the corrosivity of said oil and from approximately 0.1% to 10% of an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group of said ester.

25. A compounded hydrocarbon oil containing a metal salt of an aliphatic carboxylic acid in an amount suflicient substantially to increase the corrosivity of said oil and from approximately 0.1% to 10% of an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group of said ester.

26. A compounded hydrocarbon oil containing a metal salt of a carboxylic acid having an aryl substituent in an amount sufficient substantially to increase the corrosivity of said oil and from approximately 0.1% to 10% of an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group 7 of said ester.

27. A compounded hydrocarbon oil containing a small amount of a metal phenate having an oil-solubilizing substituent and from approximately 0.1 to 10% of an ester having as a substituent an element of the phosphorus group in a trivalent state no more than two carbon atoms removed from a carbonyl group of said ester.

28. A compounded hydrocarbon oil containing a corrosion inhibitor comprising an aliphatic ester having phosphorus in the trivalent state substituted on an 'alkyl carbon atom and no more than two carbon atoms removed from a carbonyl group of the ester.

29. The compounded hydrocarbon oil of claim 25, wherein said metal'salt of an aliphatic carboxylic acid is the salt of a partial ester of an aliphatic polycarboxylic acid.

JAMES o. CLAYTON. BRUCE B. FARRINGTON. 

